Fence charging circuit



May 31', 1949. A. WOOLLEY FENCE CHARGING CIRCUIT Filed Feb. '7, 1946 ff /7 Waaun/ Iapplied to the fence.

Patented May 31, 1949 FENCE CHARGING CIRCUIT Lee A. Woolley, Kokomo, Ind., assigner to Kingston Products Corporation, Kokomo, Ind., a corporation of Indiana Application February 7, 1946, Serial No. 646,043

2 Claims.

This invention relates to a fence charging circuit for supplying periodic high voltage surges to a fence for the purpose of retaining live stock in the enclosure deiined by the fence, and particularly to a fence charging circuit embodying safety,-

elements automatically operative to prevent the application of a voltage to the fence which would be dangerous to humans or live stock contacting such fence.

Fence charging circuits have heretofore been periodically established current flow through theV4 primary of a step up transformer. A charging condenser was connected in parallel to the Contacts of the interruptor. Periodic making and breaking of the primary circuit and the accompanying charging and discharging of the condenser produced a high voltage surge potential in the secondary of the transformer which Was While such surges were of sufficient intensity to eXert the desired restraining shock on any live stock attempting to` pass over the fence, the duration of the surge was so limited that there was no possibility in the normal operation of the circuit that the shock thus received could be fatal to either live stock or humans.

With the extension of alternating current power to many farms, there arises a need for a fence charge controlling circuit which will conveniently operate from the customary household current supply which is normally 110 volts at 60 cycles. The fence charging circuits heretofore produced for operation on alternating current have embodied two outstandingly detrimental features: first, in the event that there was a failure of the alternating current power, the fence would be cle-energized and accordingly the live stock could escape from the fenced enclosure until the alternating current supply was reestablished; secondly, and more important, it has been repeatedly observed that charged fences are particularly susceptible to being struck by lightning during a storm. Under such conditions, with the conventional alternating current supplied fence charging circuit, the current surge produced by the lightning may not only melt and secure the contacts of the interrupter together but also may produce various shorting connections within the fence charging circuit or to the metallic casing in which the control apparatus is contained, the combined result of which is the continuous application of the 110 volt alternating current to either the primary or secondary of the step up transformer. Accordingly, a continuous voltage of appreciable magnitude is thus accidentally applied to the fence and a continuous shock can be delivered to any live stock or human coming in contact with the fence in such condition. Under such conditions, the resulting shock could well be fatal.

Accordingly, it is an object of this invention to provide improved fence charging 1circuit which may be operated on alternating current with little, if possibility of accidental application of a dangerous voltage on the fence.

Another object of this invention is to provide a fence charging circuit normally operable from an alternating current supply but including connections for a low voltage D. C. Icircuit supply, such as a battery, and a relay automatically operahle to energize the fence from the D. C. source upon the occurrenceof a failure of the A. C. source supply.

A particular object of this invention is to provide an improved fence charging circuit wherein a wave trap or filter is provided in the output of the fence 4charging circuit intermediate such circuit and the fence, and said lter is effective to substantially eliminate the application to the fence of any dangerous voltages of the frequency of the alternating current source.

IThe specific nature of this invention, as well as other objects and advantages thereof, will become apparent to those skilled in the art from the following detailed description of the annexed sheet of drawings which, by way of preferred example only, illustrates one specific embodiment of the invention.

On the drawings the single gure is a circuit diagram of fence charging circuit embodying this invention.

As shown on the drawing:

A fence charging control circuit in accordance with this invention comprises a pair of A. C. input terminals 2 adapted to be lconnected to a suitable source of alternating current power, such as 110 volts, cycle current, by means of a conventional plug il. The terminals 2 are in turn connected thru suitable fuses 5 to the primary winding 6 of an input transformer 8. A line surge protective device i2 may be connected across the primary 6. Such device may `constitute any one of several ywell known forms and in general includes a The secondary I of transformer 8 is connected across the input terminals olf a full wave rectifying bridge I4 of dry disk-type rectiiying elements I6. The secondary winding I0 of transformer 8 is also connected to directly energize the coil 28 of a change over relay I8. The negative terminal 22 of the D. C output side of rectiiier bridge I4 is connectedi-to ground through a ballast resistor 24. The positivetermin'al 26 is connected to one contact 28 of the relay I8. A bypass condenser 30 is also connected across the D. C. output terminals 22 and 26 of the rectifier bridge I4. The condenser 38 is oi large capacity to insure the substantial elimination of all 'harmonic components from the D. C. output of Irectiiying bridge Ill.

A pair of D. C. input terminals 38 are provided, one of which is connected through aswitch 32 to ground, and the other of which is connected to the second xed contact 34 of relay I8. Any suitable source of low voltage D. C. power, preferably 2Q 'a sto-rage vbattery 'offsubstantially the .same voltage-as developed lbyi rectifier bridge I4 may be lconnected'to AMD. C. vinput terminals 38.

' Thel movable Contact 3850i relay I8 is connected lby' conductor-38itolthe inputlof -the charging unit lor 'surge'.generating-unitfll. The surge generat- -ingfunit-l-may comprise any one of several well known icrm's offsuch apparatus and in general comprises a step-up transformer 42 having the -primary 'Winding 4'4@thereof-periodically energized i/t'hroug'hthe conductorrSB'by'means of the inter- -rupterunit1416,'theicontacts '48 of which are connectedinseries with :primary ywinding 44. Interrupter 45 comprises l-anlos'cillating member similar .to'that shown. Land described in U. S. Patent iNo. 1,585,318, issued .Mayl', 1926, to A. W. Tupper. It willbeunderstood that the interrupter '481s onlyshown schematically in Fig. 1 and as 'shown bytheafore-mentioned patent will include ifa solenoid Knot' shown) for `producing its oscillat- .ingmovem'entffwhich solenoid iszperiodically energized by the same current flowing through contacts 48.

.Thecont'acts48of interrupter 48 when closed 'complete a -circuittoaground'so that the closing of these contactskconiplete'sf'a vcurrent vsupply cir- "cuit'ffor yprimaryfwindingf44 trom either rectier fbridge Miur-1D. `-Cvinput terminals 38, depending v uponfthe position-*.oflimovable contact 36 of relay I8. A charging-condenser L50 is'c'onnected across icontactsflI--rsofas to be :charged by the inductive -eie`c`t1of primary winding-44 `upon the opening rofcontacts'll'. Movable `contact 38 of relay i8 Iisybiased-by: a :springfSTI tol normally maintain such imovable ccntactinengagement with Xed con- .tact'3'4. IIowevenwhenthe A.' C. inputterminals 2 are connected to a suitable source of A. C. power, thel coil.2ll.of.v relay I8-isfener'gized and the movable contactf36 Aof-theJrelay isfthenrnoved into engagement with the fixed contact 28, completing a power supply circuit-fvorA the'fsurge generating unit `4,0 from the-output ofthe -rectifying bridge I4.

YFrom the1aforedescribedrconnections, it will be apparent :that'the Asurge vgenerating unit 48 is Isuppliedfro'rnxthe A. 1C. :source so long as A. C. powe'r isiavailable. Upon failure of A. C. power lforany-reason, the-movable contact 36 of relay I8 ',returns kto lits Inormal position. and immediately Lconnects the XD. 1C; input terminals 30 and the associated battery t(n'otshown) to supply power ifor'the operationzof-the-surge generating unit 48.

Thelsecondarywindingf offthe step up trans- :former 42:isjdirectly'connected to abinding post `A54. and 'the Iconnecton /fro'm the fence to be charged Knot-shown) may bef'made to binding 1 post 54 when the weather conditions have been particularly dry. A second binding post 58 is provided which is connected to secondary winding 52 through a resistor 58 and the connection 5 from the fence (not shown) may be made to binding post 58 for normal or wet weather conditions. Suitable protective gap devices 88 may be provided-respectively, connected between binding 'posts 54 and 58 and ground.

To afford an indication of the proper operation of the surge generating unit, a lamp 59 of the 'neon typefmay be connected between binding post 58 and ground through a series resistor 84. It will be=understood`that lamp 59 flashes each time that a surge voltage is applied to the fence.

The other end of secondary winding 52 of step Vup transformer 42 is connected to ground through a iilter or wave trap circuit 81, here shown as comprising the parallel connected inductor 65 and condenser 88. The filter 6l! may take any one of a variety or several well known `forms but in '.accordancefwith this invention, the characterlistics oi-illter 8'! `are'sele'cted'so as to produce a `very. high impedance. to the iiow of current in A'theoutput of vthe-surge generating unit of the fsam'e irequencyfasthat of the alternating current source; `further, the characteristics of lter ele- 1ment'65 are selected toa-yield a very low impedance to current of the frequency corresponding to the surges Ygenerated'by the surge generating unit 40. The operation of the `fence charging circuit yembodying `this finvention is deemed obvious in Viewoi'thei'oregoing description. A D. C. current is supplied `to theinput of the surge generating Vunit ll'from eitherthelD. C. input terminals 30 yor the output of the rectilfying bridge I4 dependent uponithe existence of alternating current power across the A.'C.input terminals 2. However, the current-flow through the primarywinding 44 of step up transiormer'42l occurs only while the contacts 48 @of the oscillating interrupter 48 are vclosed `or immediately following the opening of such contacts `when the inductance of primary winding l4'4 produces vadischarge through charg- "ing .condenser 58. Thus each time that the oscilflatinginterrupter-ll makes and breaks the D. C. lcircuit through the primary'44 of step up transformer '42, a surgevoltage-ls produced in the secvondarywinding 52 which is applied to the fence (not shown).

In^the1eVentthat aishorting connection is produced anywhere withinlthe ycircuit lby lightning `or other accidentlsuch that the A. -C. voltage is supplied'to'either the` primary or secondary cir- 55 -cuit off-step-up transformer 42, it is apparent that fsuch A. C. voltage willfalso be applied to the fence.

"However, due to the highirnpedance of the filter felement 61? tofcurrents of the frequency of the A C. source, theintensity of^current flow of Such :frequencyfthat-willoccuriupon the contact or live- Astock-orhurnans with lthe fence will be Vreduced by'ilter'l-to-a Value below that which can prove Vharmful -to :either livestock -or humans. Accordfingly, circuitdisarrangement produced by lightning'orianyother cause will not operate to impress `a dangerous A. C. voltage onthefence. Furthermore, yupon the :failure of A. C. power for any freascn, the Iautomatic changeover relay I8 im- `rmediately.functions Vto energize the surge vgenerating unit fromthe D.'C. source and thus insures that the ien'ce'is continuously charged. Restora- `tion'of A. lC. power automatically cuts out the :D.C. source.

It will, ofcourse, be understood that various details Volficonstruction-Imay be varied through a wide range without departing from the principles of this invention and it is, therefore, not the purpose to limit the patent granted hereon otherwise than necessitated by the scope of the appended claims.

I claim as any invention:

1. A fence charging circuit comprising A. C. input terminals adapted to be connected to a source of alternating current, D. C. input terminals adapted to be connected to a source of D. C. current, rectifying means connected to said A. C. input terminals, surge generating means responsive to direct current for periodically producing high voltage surges, circuit means for supplying said surges to a fence independently of current from said alternating current source and said circuit means including filter means responsive to current of the frequency of said source but not to said high voltage surges for substantially eliminating current 110W o\f the frequency of said source in said circuit means, and relay means normally connecting said surge generating means to said D. C. terminals and responsive to application of alternating current to said A. C. input terminals to disconnect said surge generating means from said D. C. terminals and to connect said surge generating means to said rectifying means.

2. A fence charging circuit comprising A. C. input terminals adapted to be connected to a source of alternating current, D. C. input terminals adapted to be connected to a source of D. C. current, rectifying means connected to said A. C. input terminals, surge generating means responsive to direct current for periodically producing high voltage surges having a frequency different from the frequency of said alternating current source, a circuit adapted to supply said high Voltage surges to a fence independently of current from said alternating current source, said circuit including a series connected filter having a high impedence at the frequency of said source and substantially negligible impedence to said voltage surges, a relay, and means for energizing said relays from said A. C. terminals, said relay being arranged to connect said surge generating means to said rectifying means When said relay is energized and to connect said surge generating means to said D. C. terminals when said relay is deenergized.

LEE A. WOOLLEY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Re. 20,725 Heidger May 17, 1938 1,169,537 Gugler et al Jan. 25, 1916 1,362,081 Chubb Dec. 14, 1920 2,415,944 Fagen Feb. 18, 1947 

